package com.test;

import java.util.ArrayList;
import java.util.List;

/**
 * Created by guojin on 2018/9/25.
 */
public interface A {

    default void doTest() {
        System.out.println("这是默认方法");
    }


    public static void main(String[] args) {
        int[] a = {1, 2, 5, 4};
        System.out.println(a.length);
        System.out.println(a[3]);

        String s = "abcde";
        System.out.println(s.length());
        System.out.println(s.toCharArray()[0]);


        List<String> list = new ArrayList<>();
        list.add("a");
        list.add("b");
        list.add("c");
        list.add("d");
        System.out.println(list.size());
        System.out.println(list.get(0));

    }

}
